a) Field of the Invention
The present invention relates to a hydraulic power generating device in which hydraulic power generation is performed by using the flow of city water ejected from a faucet or the like.
b) Description of the Related Art
An automatic faucet device has been spreading which is constructed such that water flows out from a faucet automatically when a hand is stretched out at a downward position of the faucet and a sensor detects it. Further, in recent years, a small-sized hydraulic power generating device has been provided at a midway position in the flow passage of city water to store electric power obtained by the hydraulic power generating device and to supply the stored electric power to the sensor circuit of an automatic faucet device.
A conventional hydraulic power generating device includes a main body case forming a flow passage provided with a water wheel chamber between a fluid inlet port and a fluid outlet port and a cover covering the upper face of the main body case. An ejection port includes a groove formed on the upper face of the main body case so as to be located between the main body case and the cover body for ejecting fluid toward the blades of a water wheel for power generation within the water wheel chamber at a high speed. The fluid is ejected toward the blades of the water wheel at a high speed to generate electric power. (for example, refer to Japanese Patent Laid-Open No. 2002-81361).
In such hydraulic power generating device, the fluid is ejected toward the blades of the water wheel within the water wheel chamber from the ejection port at a high speed and thus the water wheel for power generation can be efficiently rotated even at a little flow rate.
Also, in the case that a discharge space in communication with a fluid outlet port is constructed at a downward position of the water wheel chamber, the fluid having rotated the water wheel flows on the lower side smoothly in comparison with the construction that the water wheel chamber is directly in communication with the fluid outlet port and thus the efficiency of power generation improves.
Since such hydraulic power generating device is used under various conditions, hydraulic power generating devices of various specifications are required. For example, when the resistance of water passage or the flow rate is different, the quantity of power generation also varies. Therefore, the aperture size of the ejection port for ejecting the fluid to the blades of the water wheel is required to be changed depending on the operating condition. However, when the main body case is produced for every specification, the cost of the molding die for producing the main body case is remarkably increased and a short time of delivery can not be attained.
Further, when the discharge space in communication with the fluid outlet port is constructed at a downward position of the water wheel chamber, an impact sound may occur although the efficiency of power generation is improved. As a result that the present inventors have investigated thoroughly about the cause of such an impact sound, he has found that, in the discharge space, a part of the fluid circulates at a high speed and air bubbles entered into the fluid are not discharged toward the fluid outlet port from the discharge space to turn around while repeating deformation such as compression and expansion, which causes to generate an impact sound.